Photograph by Joel Sartore, National Geographic Photo Ark


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This female North American porcupine was photographed at the Great Plains Zoo, Sioux Falls, South Dakota.

Photograph by Joel Sartore, National Geographic Photo Ark


Prickly porcupines mate without hurting each other. Here’s how.

Behind every baby porcupine, there’s a reproduction ritual that involves tree fights, urine squirts, and covering quills during copulation.

This story appears in the August 2020 issue of National Geographic magazine.

As an observer of the North American porcupine for more than 30 years, Uldis Roze has no idea how many times he has heard this joke.

How do porcupines reproduce? Very carefully.

That answer is “correct, but not very enlightening,” says Roze, a professor emeritus of biology at New York’s Queens College. In reality, the mating ritual of the quill-covered Erethizon dorsatum is quite elaborate, protracted, and … damp.

The species’ annual mating season is in early fall. In her chosen tree, the female signals she’s about ready to breed by secreting an odoriferous substance. Males drawn by the smell fight each other in the tree branches and on the ground below her. The one not knocked out wins mating rights—but the seduction’s not done.

To induce estrus in the female, the male squirts her with urine, a few drops at a time. The urine is “propelled at such high velocity,” Roze says, “that even if a male and female are sitting on separate branches in a tree, his urine can reach her.” The male keeps it up—“repeated salvos over many hours,” Roze says—until the female is in the mood. Typically, the two then descend the tree to breed.

Quills could make mounting the female a prickly proposition. But when she’s ready, the female curves her tail over her spiky back so her tail’s quill-free underside is facing up, Roze says. The male then can rest his paws on that surface while doing the deed.

Approximately seven months later, the female will give birth—in this species, usually a single offspring. Known as a porcupette (read more about the names for baby animals), the baby is born with all its quills but also wrapped in the amniotic sac that smooths the little one’s arrival.